Não consigo lembrar o nome desse anime. Havia monstros amarelos, e as pessoas que lutavam contra eles usavam grandes ternos de máquina. Quanto mais eles usavam os ternos, mais eles se transformavam em cristais e acabavam morrendo. Estava situado em uma ilha, e havia uma garota na ilha que de repente cresceu desde criança.
Fafner no Azure (2004), provavelmente.
A partir de Myanimelist:
Tatsumiyajima is the central island in the middle of a small cluster of islands, in a sleepy backwater of the Japanese isles. Not much happens there, and the island's young people go to school knowing that their lives are likely to remain peaceful and undisturbed. Or so they have been taught... but the truth is different. The fate of mankind is on the line, and Tatsumiyajima is the last line of defense against a hostile and incomprehensible enemy. At the center of it all, fighting for Humanity's continued existence, is the giant robot Fafner, the dragon that guards this final treasure of mankind.
Os monstros amarelos seriam o Festum:
Os Festum têm um processo de "assimilação", pelo qual o alvo é cristalizado, despedaçado e incorporado à sua mente colméia (o Mir). Os Fafner (os grandes mecha que os humanos usam para combater o Festum) usam componentes Mir, e isso faz com que você se lembre: (informações retiradas do Fafner Wiki)
Due to the use of Mir fragments in the construction of many Fafner models, their internal cores gradually assimilate pilots with each activation, in largely the same manner as Festum. The rate of assimilation varies wildly between models, but given time, every core-equipped Fafner will inevitably attempt to consume its pilot. [...]
In the worst of cases, the Fafner will begin attacking its pilot's mind, leaving them comatose and unable to continue piloting. Without proper treatment, comatose victims or other severe cases will eventually succumb to complete assimilation, their body crystallizing entirely and shattering, just as Festum victims do.
Veja esta mulher piloto, por exemplo (S01E23, "Decoy"):
E a abertura para uma boa medida:
Encontrado com a consulta do Google anime mecha "turn * crystal" - "coroa culpada" que retornou isso respondeu à pergunta do Yahoo, que provavelmente estava procurando a mesma coisa:
What was that mecha anime where they would turn to crystal when they were defeated? If i remember right they were on a moving island to prevent them from being located. I just remember that when they lost they would have crystals growing all over there mech's